The present invention generally relates to bolt torque sequence templates, and more specifically, but not exclusively, concerns a disposable head bolt torque sequence template.
In order to properly rebuild an internal combustion engine, cylinder head bolts of the engine must be tightened in the proper sequence. Tightening of the head bolts in the proper sequence ensures proper compression of the head gasket between the engine block and the cylinder head of the engine. Improper tightening of the head bolts can warp the cylinder head. Typically, a mechanic consults a shop manual and follows a torque sequence listed in the shop manual for the particular engine. However, since each engine family generally has a unique torque sequence, there is a risk that the wrong sequence will be mistakenly used. The print in the service manual is also rather small and can be easily misread. Further, errors may occur because the service manual may not be kept up to date.
One solution to this problem has been to purchase a non-disposable, plastic template for each engine type. Storage of these templates can be problematic, and the templates can be easily lost. After being used a number of times, the template can become dirty, which can make reading of the template difficult. Future engine designs are leaning towards using even more head bolts per engine, and for each new design, a different template has to be ordered. If not ordered, the templates may not be available when needed.
In another solution to this problem, torque sequence numbers are imprinted or embossed on a valve cover gasket at positions near the bolts. For embossing, the tooling needs to be specially designed in order to form the torque sequence numbers on the valve cover gasket. Both embossing and imprinting the torque sequence numbers increases the risk of damaging the valve cover gasket and increases the cost of the valve cover gasket. Furthermore, using the valve cover gasket as a template requires that the valve cover gasket be installed prior to tightening of the bolts. This can increase the risk of damaging of the valve cover gasket. Therefore, there has been a long felt need for a head bolt torque sequence template that is readily available and easy to use.
One form of the present invention concerns a torque sequence template. The template includes a head gasket backing constructed and arranged to support a head gasket when packaged with the head gasket. The backing has at least two bolt openings defined therein at positions corresponding to positions of bolts that compress the head gasket between a cylinder head and an engine block. The backing has a torque sequence indicator provided next to each of the bolt openings for indicating a torque sequence for the bolts.
Another form concerns a package that includes a head gasket and a head gasket backing. The backing supports the head gasket. The backing has at least two torque sequence indicators arranged thereon to indicate a torque sequence of bolts that compress the head gasket between a cylinder head and an engine block.